The invention relates to bandsaw blades and in particular to the aligning of bandsaw blade strip ends prior to welding.
Bandsaw blades are generally made by welding appropriate lengths of toothed steel strips into loops fitting a bandsaw machine. In the bandsaw machine the bandsaw blade runs over two large pulleys, and sawing of the work material occurs along one of the straight stretches approximately midway between the pulleys. For narrow bandsaw blades such as used for sawing metal and in the furniture industry, the resistance to torsion is so low, that it is necessary to position saw blade guides immediately below and above the work material, for supporting the bandsaw blade on its sides as well as on its rear toothless edge. For proper operation it is important that the welded joint be as straight as the rest of the bandsaw blade, with no step or angular change disposed therein.
In many cases the toothed strip is manufactured straight, so aligning the ends before welding them together is rather easy. With modern high strain bandsaws, especially for metal sawing, however the strip is deliberately made with a slightly shorter rear edge to offset the effect of letting the toothed front edge run outside the pulleys. This makes the band have a curvature in its plane, called camber, when it is not under tension in the machine. The amount of camber may be chosen with reference to the width of the strip and the expected work load. This makes alignment of the strip ends very difficult.
The present invention relates to a method and apparatus for ensuring that the strip ends are aligned as to position and direction when welding them together.